The main objectives of this project are (i) to identify the helper virus genes that regulate expression of defective human parvovirus (AAV) genomes, and (ii) to define their respective roles in AAV replication. We previously mapped the adenovirus genes required for AAV replication and continue to investigate their specific helper functions. Similar studies are in progress with herpes simplex viruses. Among methods used are specific immunofluorescence, DNA cloning, gel electrophoresis, blot- hybridization analyses, and DNA transfection of both simian and human cell lines.